In the production of round pattern drums or templates it is known to apply a photosensitive lacquer to a perforated foil and to expose the photosensitive lacquer through a desired mask so that, by development of the photolacquer, desired perforations of the foil are exposed to enable screen printing to be effected therethrough.
It is also known to produce a screen printing drum of the aforedescribed type to coat a perforated foil with a material which can be evaporated or destroyed by a laser beam and then to expose the perforations in the desired pattern by focusing the laser beam at which this coating material is to be removed.
In this system, the silk screen pattern blank is drawn over a circumferentially expandable support cylinder which, in the expanded state, runs perfectly round or to mount the silk screen blank over a shaft having support bodies therealong, the movement of the support bodies which are shiftable along the shaft and the laser head being coordinated with one another to ensure effective bracing at the site of the blank upon which the laser beam is trained. In devices of the latter type the positioning of the screen printing pattern blank cannot be automated.